Conventionally, the GaN-based light-emitting diode device has a structure of forming a metal light reflecting layer on a back surface of the GaN-based semiconductor structure having a light-emitting layer, thus the light-emitting layer can have enhanced light extraction efficiency. Basically, the metal light-reflecting layer is made by some specific metals, such as silver. However, because the manufacturing environment with high temperature or high humidity, the silver ions in the metal light-reflecting layer may have the migration effect and consequently the metal light reflecting layer may have lower reflection efficiency.
Conventionally, the above-mentioned problems can be fixed by employing a protective structure so surround the metal light-reflecting layer. However, even being capable of preventing the aforementioned migration and oxidation problems from occurring, the conventional protective structure has a poor adhesion degree with the metal light reflecting layer due to the conventional protective structure basically is made metal oxide, and consequently the light-emitting device may have lower reliability.
Thus, there is a need to provide a new structure of light-emitting diode device with an enhance reliability.